1 . Instead of ________ (criticize), little Tom was rewarded with high praise. （所给词的适当形式填空）

2 . The password was whispered into his ear in order to avoid ________ (hear) by others. (所给词的适当形式填空)

3 . To prevent the world from ________ (pollute) by cars, we will have to make some changes in the way many of us live. （所给词的适当形式填空）

4 . ________( appreciate) by others is something that always makes people happy.

5 . The detective Sherlock disguised (伪装) himself and secretly followed the president without ______________ (recognize). （所给单词适当形式填空）